Active seat suspension

Abstract

An active suspension for a driver seat of a bus or a heavy vehicle which comprises an electric actuator allowing the exertion of the force between the floor of the vehicle and the bottom of the seat. The adjustment of the height of the seat is accomplished by an electric actuator or by an independent mechanical system. A controller generates a control force calculated from measurements obtained by sensors located at different locations on the suspension. Forces exerted by the electric actuator can be relieved by passive element placed in parallel which cannot assume by themselves the role of a suspension for a given application.

Description

INTRODUCTION [0001] The present invention generally relates to an active suspension system for a vehicle driver seat, notably in a buss, a heavy vehicle or a specialized use vehicle, for example, an excavating or forestry equipment, and of which the operator or driver is submitted to vibrations. BACKGROUND OF THE INVENTION [0002] It is known that irregularities in roads cause the presence of important vibrations in the driver cab for bus drivers or drivers of heavy vehicles such as trucks or specialized use vehicles, for example, excavating or forestry equipment. Exposures of drivers to these vibrations make the exercise of their work uncomfortable and can have a negative influence on their health. In order to reduce the acceleration transmitted to the level of the driver's seat, a suspension is often introduced between the vehicle floor and the seat. The seat suspension must minimize the acceleration transmitted to the driver, but must also maintain minimal the gap in position betw...

AI Technical Summary

Benefits of technology

[0021] More specifically, the object of the present invention is to provide an active suspension for a vehicle driver seat, such for use on a bus, a heavy vehicle or a specialized use vehicle, for example excavating equipment or forestry equipment, in which the operator or the driver is submitted to vibrations, and that comprises an electric actuator allowing to exert a force between the vehicle floor and the seat. The adjustment of the height of the seat is accomplished by an electric actuator or by an independent mechanical system. A controller generates a force command calculated from measur

Problems solved by technology

It is known that irregularities in roads cause the presence of important vibrations in the driver cab for bus drivers or drivers of heavy vehicles such as trucks or specialized use vehicles, for example, excavating or forestry equipment.

Exposures of drivers to these vibrations make the exercise of their work uncomfortable and can have a negative influence on their health.

Therefore, a very soft suspension will allow a considerable reduction in the level of transmitted acceleration, but at the cost of a significant relative displacement.

However, a suspension that is too stiff will maintain a good interaction between the driver and his driving area, but will only offer a weak reduction in the transmitted acceleration.

Back or health problems observed despite the use of this type of suspension demonstrate that passive suspensions do not allow to reach a sufficient level of comfort.

Phase 2: Évaluation de sièges candidats, IRSST, June 1997) demonstrate however that their performance in this use is not appreciably better than the performance of passive suspension having fixed dampening.

These systems have been, in the great majority, put into practice with the help of hydraulic actuators that present several inconveniences, notably of being voluminous, of having a high cost and an excessive consumption of energy and requiring delicate maintenance.

This type of configuration implies that the elements that comprise these passive suspension systems, that are notably the spring element and the dampening element, possess characteristics that cause a passive transmission path between the floor of the vehicle and the base of the seat which is relatively important, resulting thus in relatively high values of stiffness and dampening.

The disadvantage related to active suspension systems that are coupled in parallel with a traditional passive suspension, that is to say capable of functioning autonomously and having relatively high values for stiffness and dampening, are the following: 1.

When the passive elements are significant, they act on all of the frequency bandwidth, and therefore the controller, so that the suspension can be effective, must compensate this passive transmission path over the complete bandwidth, which is difficult to realize in practice given that the presence of noise on the sensors limits the useful bandwidth of the controller.

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